Functionalised materials, process for the production and uses thereof

ABSTRACT

The invention relates both to processes for the production of functionalised materials containing alkyl sulfonic acids groups and their use as heterogeneous catalysts. The invention also relates to precursors of these new products and new organopolysiloxane sulfonic acids.

The invention relates both to a process for the production offunctionalised materials containing alkyl sulfonic acid groups and theiruse as heterogeneous catalysts. The invention also relates to precursorsof these new products and new organopolysiloxane sulfonic acids.

There is a growing requirement in the chemical industry for effectiveheterogeneous catalysts to replace homogeneous reagents and catalysts.This requirement is as a consequence of stricter environmentalregulations, the need to avoid and reduce solid and liquid waste levelsalong with the drive to lower energy consumption. For example there is aneed for effective heterogeneous acid catalysts that can replacesulfuric acid, hydrogen fluoride or phosphoric acid. Additionaladvantages include ease of work up as heterogeneous acid catalysts canbe readily separated whilst homogeneous catalysts require extensive workup and separation and so produces additional waste. Further advantagesinclude being able to reuse the heterogeneous catalyst, selectivity forthe production of the desired product and high thermal and physicalstability. Further potential advantages include tuning the acid strengthso as to avoid side reactions. For example sulfuric acid often producescoloured products that have to be purified. The additional purificationprocess invariably produces additional waste and invariably requiresadditional energy consumption.

Sulfonic acid containing polymers and materials are used for a varietyof purposes including purification of aqueous streams through theremoval of metal ions and also as solid acid catalysts. The most commonmaterial is based on a sulfonated polystyrene polymer. The chemical andphysical properties of such polystyrene based systems are described inthe Bio-Rad Life Science Research Products catalogue 1998/99, pages56-64. However the physical and chemical properties of these polystyreneresins may possess disadvantages, for example poor chemical stabilityand thermal stability, believed to be due to the organic polymericbackbone. Additional problems for example swelling and shrinking inorganic solvents as well as the production of highly coloured unwantedside products may also be encountered. The swelling may cause problemsin space use efficiency of reactors and production yield. Generally, dueto their poor thermal stability, these polystyrene resins cannot be usedfor any length of time above 80° C., thus limiting their generalapplicability.

Inorganic polymer systems such as silica, aluminium oxide and titaniumoxide have also been disclosed as functionalised materials. Activefunctional groups or metals can be attached by a variety of means tothese systems. However a number of problems may be encountered where thefunctional groups are only physically adsorbed for example lowfunctional group loading, limitations in the range of solvents that canbe used, and removal of the functional groups during use or on standing.This is believed to be due to the rather weak attachment between thefunctional group and the surface atoms on the support. Building thefunctional group into the framework may provide a more robust materialand may also allow higher functional group loadings. However in thisapproach there is a significant lack of readily available startingmaterials as well as precursors for preparing such starting materials.In addition there are limited synthetic methodologies for thepreparation of suitable starting materials from available precursors. Aneed exists to provide new synthetic methods as well as startingcompounds in order to make such functionalised materials. In additioneven if such substrates are available the chemical processes to make thedesired solid materials are invariably multi step, complex and leadingto low yields and likely low functional group loadings of product thatcannot be purified.

Acid catalysts based on propyl sulfonic acid attached to silica havebeen reported in U.S. Pat. No. 4,552,700. The process as described tomake these catalysts involves multiple chemical steps and intermediateisolation and as a consequence has significant cost and manufacturingissues. In reality these processes are limited to the preparation of thepropyl sulfonic acid material. Existing chemistry to make the ethylsulfonic acid attached to silica is even more limited. One possibleapproach would involve a multi step process to first make and isolatethe intermediates (R¹O)₃SiCH₂CH₂SH or [(R¹O)₃SiCH₂CH₂]₂S_(n).followed byoxidation and grafting. The intermediates can be formed in low yieldthrough reaction with the unstable and not readily available(R¹O)₃SiCH₂CH₂Cl. This is not a realistic industrial process. Thesynthesis of these intermediates was reported in 1968 by Gornowicz etal. J. Org. Chem 1968. 33, 2918-2924 and again involved a multi stepchemical process with a purification step. Vinyl trimethoxysilane wasadded into a heated mixture of thioacetic acid andazobisisobutyronitrile to give a mixture of (CH₃O)₃SiCH₂CH₂SC(═O)CH₃ and(CH₃O)₃SiCH(CH₃)S—C(═O)CH₃. Distillation was then required in order toseparate (CH₃O)₃SiCH₂CH₂S—C(═O)CH₃ from its by-product(CH₃O)₃SiCH(CH₃)S—C(═O)CH₃. A second step involved the treatment ofthese compounds with sodium methoxide to form the desired compound(CH₃O)₃SiCH₂CH₂SH. Another process to prepare (R¹O)₃SiCH₂CH₂SH wasdescribed in GB791609. In this case, vinyl triethoxysilane was refluxedwith hydrogen sulfide under ultra-violet light. The drawback of thismethodology is that the reaction takes place very slowly in the absenceof ultra-violet light and this methodology does not lend itself to largescale manufacture.

Oxidation of (R¹O)₃SiCH₂CH₂SH or [(R¹O)₃SiCH₂CH₂]₂S_(n) to the desiredintermediate (R¹O)₃SiCH₂CH₂SO₃H is problematic and no successful reportsof this chemical transformation could be found in the literature.Likewise no reference could be found for the silanol (HO)₃SiCH₂CH₂SO₃H.

It is an object of the present invention to provide processes for theproduction of ethyl sulfonic acids covalently attached to an inorganicmaterial such as silica. A further object of the present invention istheir use as heterogeneous catalysts.

In the first aspect the invention provides a process for the productionof a compound of Formula I:[(O_(3/2))Si CH₂CH₂SO₃X]_(a) [Si(O_(4/2))]_(b) [VSi(O_(3/2))]_(c)  (I)wherein:

X is selected from H, or M where M is a base or transition metal ion;

V is a monovalent group which is optionally substituted and selectedfrom a C₁₋₂₂-alkyl group, C₂₋₂₂-alkenyl group, a C₂₋₂₂-alkynyl group,C₁₋₂₂-alkylaryl group, an aryl group, a C₂₋₂₀-alkyl sulfide C₁₋₂₂ alkylgroup, C₂₋₂₀-alkylene sulfide alkyl group, a C₂₋₂₀-alkyl sulfide arylgroup, a C₂₋₂₀-alkylene sulfide aryl group;

the free valences of the silicate oxygen atoms are saturated by one ormore of:

a silicon atom of other groups of Formula I, hydrogen, a linear orbranched C₁₋₂₂-alkyl group, an end group R₃SiO_(1/2), a cross-linkingbridge member or by a chain R_(q)Si(OR¹)_(g)O_(k/2) orAl(OR¹)_(3-h)O_(h/2) or RAl(OR¹)_(2-r)O_(r/2), wherein R and R¹ areindependently selected from a linear or branched C₁₋₁₂ alkyl group, anaryl group and a C₁₋₂₂ alkylaryl group, k is an integer from 1 to 3, qis an integer from 1 to 2 and g is an integer from 0 to 2 such thatg+k+q=4, h is an integer from 1 to 3; and r is an integer from 1 to 2;and, when present, the ratio of the mole sum of the end group, crosslinker and/or polymer chain to a+b+c is from 0 to 999:1

a, b and c are integers such that the ratio of a:b is from 0.00001 to100000, a and b are always greater than 0 and when c is greater than 0the ratio of c to a+b is from 0.00001 to 100000;

the process comprising contacting in any order or simultaneously:

a) a compound of Formula II or precursor components of the compound ofFormula II,(R³O)₃SiCH₂CH₂SC(═O)R²  (II)

where R³ is hydrogen or a C₁₋₆ alkyl group and R² is a C₁-₂₂ alkylgroup,

b) an inorganic support selected from silica, silica aluminate andalumina or with a compound selected from Si(OR¹)₄ and mixture ofSi(OR¹)₄ and Al(OR¹)₃; and optionally one or more of (R³O)₃SiV,RSi(OR³)₃, (R)₂Si(OR³)₂ and (R)₃Si(OR³), Al(OR³)₃ and RAl(OR³)₂; and

c) nitric acid or hydrogen peroxide;

to produce the compound of Formula I.

The reactants are contacting under such conditions of reaction time,temperature and pressure and relative quantities that they react toproduce the compound of Formula I.

In a preferred embodiment the precursors of compound of Formula IIinclude vinyl trimethoxy silane and thioacetic acid and these arereacted together and then contacted with silica and nitric acid toproduce a compound of Formula I.

The invention further provides to a process for the production ofcompounds of Formula I:[(O_(3/2))SiCH₂CH₂SO₃X]_(a) [Si(O_(4/2))]_(b) [VSi(O_(3/2))]_(c)where X is H or M where M is a transition or base metal salt; V is agroup which is optionally substituted and selected from a C₁₋₂₂-alkylgroup, C₁₋₂₂-alkylaryl group, an aryl group, a C₂₋₂₀-alkyl sulfide C₁₋₂₂alkyl group, C₂₋₂₀-alkylene sulfide alkyl group, a C₂₋₂₀-alkyl sulfidearyl group, a C₂₋₂₀-alkylene sulfide aryl group; the free valences ofthe silicate oxygen atoms are saturated by one or more of:

a silicon atom of other groups of Formula I, hydrogen, a linear orbranched C₁₋₂₂-alkyl group, an end group R₃M¹O_(1/2), a cross-linkingbridge member or by a chain R_(q)M¹(OR¹)_(g)O_(k/2) orAl(OR¹)_(3-h)O_(h/2) or RAl(OR¹)_(2-r)O_(r/2);

wherein

M¹ is Si or Ti; R and R¹ are independently selected from a linear orbranched C₁₋₂₂ alkyl group, an aryl group and a C₁₋₂₂-alkylaryl group;

k is an integer from 1 to 3, q is an integer from 1 to 2 and g is aninteger from 0 to 2 such that g+k+q=4;

h is an integer from 1 to 3; and

r is an integer from 1 to 2;

or an oxo metal bridging system where the metal is zirconium, boron,magnesium, iron, nickel or a lanthanide;

a, b and c are integers such that the ratio of a:b is from 0.00001 to100000 and a and b are always present and when c is greater than 0 theratio of c to a+b is from 0.00001 to 100000.

Where an end group and/or cross linker and/or polymer chain is used, itis preferred that the ratio of end group, cross linker or polymer chainsto a+b+c is from 0 to 999:1 preferably 0.001 to 999:1 and especially0.01 to 99:1.

The optionally substituted linear or branched group selected fromC₁₋₂₂-alkyl, C₂₋₂₂-alkenyl, C₂₋₂₂-alkynyl group, an aryl andC₁₋₂₂-alkylaryl group, R and R¹ groups may independently be linear orbranched and/or may be substituted with one or more substituents butpreferably contain only hydrogen and carbon atoms. If substituents arepresent, they may be selected independently from nitro, chloro, fluoro,bromo, nitrile, hydroxyl, carboxylic acid, carboxylic esters, sulfides,sulfoxides, sulfones, C₁₋₆-alkoxy, a C₁₋₂₂-alkyl or aryl di substitutedphosphine, amino, amino C₁₋₂₂-alkyl or amino di (C₁₋₂₂-alkyl) orC₁₋₂₂-alkyl phosphinic or phosphonic group.

Preferably, the optionally substituted linear or branched group selectedfrom C₁₋₂₂-alkyl, C₂₋₂₂-alkenyl, C₂₋₂₂-alkynyl group, an aryl andC₁₋₂₂-alkylaryl group, R and R¹ are independently selected from linearor branched C₁₋₂₂ and desirably C₁₋₁₂-alkyl, C₂₋₂₂- and desirablyC₂₋₁₂-alkenyl, aryl and a C₁₋₂₂-alkylaryl group and it is especiallypreferred that these groups are independently selected from a linear orbranched C₁₋₈-alkyl, C₂₋₈-alkenyl, aryl and a C₁₋₈-alkylaryl group.

Suitable groups R and R¹ are independently a C₁₋₆-alkyl group forexample methyl or ethyl, or a phenyl group. Preferably q is from 0 to 2,k is from 1 to 3 and g is 0 provided that g+k+q=4.

Examples of suitable alkyl groups include methyl, ethyl, isopropyl,n-propyl, n-butyl, tert-butyl, n-hexyl, 2-hexyl n-decyl, n-dodecyl,cyclohexyl, n-octyl, cyclooctyl, iso-octyl, hexadecyl, octadecyl,iso-octadecyl and docosyl. Examples of suitable alkenyl groups includeethenyl, iso-propenyl, cyclohexenyl, octenyl, iso-octenyl, hexadecenyl,octadecenyl, iso-octadecenyl and docosenyl.

C₁₋₆-alkoxy refers to a straight or branched hydrocarbon chain havingfrom one to six carbon atoms and attached to an oxygen atom. Examplesinclude methoxy, ethoxy, propoxy, tert-butoxy and n-butoxy.

The term aryl refers to a five or six membered cyclic, 8-10 memberedbicyclic or 10-13 membered tricyclic group with aromatic character andincludes systems which contain one or more heteroatoms, for example, N,O or S. Examples of suitable aryl groups include phenyl, pyridinyl, andfuranyl. Where the term “alkylaryl” is employed herein, the immediatelypreceding carbon atom range refers to the alkyl substituent only anddoes not include any aryl carbon atoms. Examples of suitable alkylarylgroups include benzyl, phenylethyl and pyridylmethyl.

Compounds where c is zero and the ratio of b:a is from 10,000 to 0.2 arepreferred.

It is an object of the present invention to provide convenientindustrial scale processes for the manufacture of compounds of Formula Iin which product yields, costs, scale and/or purities are commerciallysatisfactory, and improved with respect to the prior art.

Without wishing to be bound by any theory, it is believed that the newprocesses proceed via the radical addition of thioalkanoic acid ontovinyl trialkoxysilane to provide compounds of Formula II(R¹O)₃SiCH₂CH₂SC(═O)R². Suitable groups for R² are a C₁₋₁₂-alkyl groupor aryl group and preferred examples are methyl, ethyl or a phenylgroup.

In one process, treatment of (R¹O)₃SiCH₂CH₂SC(═O)R², where both R¹ andR² are methyl, with nitric acid at temperatures from 20-130° C. for0.1-48 hours followed by a grafting reaction with an inorganic materialsuch as silica in a solvent such as but not limited to water or tolueneat temperatures of between 60-130° C. for 1-48 hours gives compounds ofFormula I where c is zero. The inclusion of compounds (R¹O)₃SiV in thegrafting reaction with the inorganic material provides a process to makecompounds of Formula I where c is greater than zero. The advantages ofthis process include the de-protection and oxidation of compounds ofFormula II to a desired intermediate in a one step reaction thatrequires no isolation and purification; the desired intermediate is in aform that can be readily grafted onto an inorganic material without anymanipulation and in cheap solvents such as water; the component c can bereadily added to the process; the manufacture is scalable and can beperformed in one reactor without any isolation of the intermediatesinvolved; and the process proceeds in high product yield.

The invention also provides novel precursor compounds for Formula I, theprecursor being of Formula III [(R⁴O)₃SiCH₂CH₂SO₃X] wherein X isselected from H or M where M is a base or transition metal ion; and R⁴is selected from hydrogen and a C₁₋₂₂ alkyl group.

The invention also provides a process of producing compounds of FormulaIII [(R⁴O)₃SiCH₂CH₂SO₃X] comprising reacting a compound of Formula IIwith 20-100% nitric acid at temperatures from 60-130° C. for 0.1-12hours.

In another variation of these processes, treatment of(R¹O)₃SiCH₂CH₂SC(═O)R² with a hydrogen peroxide solution containingsulfuric acid at temperatures from 0-110° C. for 1-48 hours followed bya grafting reaction with an inorganic material such as silica in asolvent such as but not limited to water at temperatures of between60-130° C. for 1-48 hours gives compounds of Formula I where c is zero.The inclusion of compounds such as (R¹O)₃SiV in the reaction with theinorganic material provides a process to make compounds of Formula Iwhere c is greater than zero.

In an alternative process, treatment of compounds of Formula II(R¹O)₃SiCH₂CH₂SC(═O)R² with an inorganic material such as silica in asolvent or combination of solvents at temperatures of between 60-130° C.for 1-48 hours, followed by filtration, washing and then reaction withnitric acid at temperatures from 20-130° C. for 0.1-48 hours givescompounds of Formula I where c is zero. The inclusion of compounds(R¹O)₃SiV in the reaction with the inorganic material provides a processto make compounds of Formula I where c is greater than zero.

The advantages of these processes include the de-protection andoxidation can be conducted in one step; the component c can be readilyadded to the process to lead to compounds of Formula I where c isgreater than zero; the manufacture is scalable and can be performedwithout isolation of the intermediates involved; and the processesproceed in high product yield.

The concentration of the nitric acid in these processes can vary from 20to 100% with 50-70% being preferred.

A wide range of solvents and combination of solvents can be used for thegrafting reaction between the intermediate and the inorganic materialand include aliphatic or aromatic hydrocarbons, alcohols, polar solventslike dimethyl formamide, and water. Preferred solvents are toluene andxylene. Preferred inorganic materials include silica, alumina and silicaaluminates.

Compounds of Formula I can also be prepared using sol gel processes forthe formation of the silica framework. The solution obtained fromtreatment of compounds of Formula II (R¹O)₃SiCH₂CH₂SC(═O)R² with nitricacid at temperatures from 20-110° C. for 1-48 hours is combined withtetraethyl orthosilicate in an aqueous alcohol solvent. The solution wasallowed to stand at 20-80° C. for 1 to 30 days and the resultant solidwas dried, washed and milled to the desired particle size of compoundsof Formula I where c=0. Compounds of Formula I where c is greater thanzero are formed through the addition of (R¹O)₃SiV along with thetetraethyl orthosilicate.

The invention also provides novel compounds of Formula I:[(O_(3/2))Si CH₂CH₂SO₃H]_(a) [Si(O_(4/2))]_(b) [VSi(O_(3/2))]_(c)wherein V is a group which is optionally substituted and selected from aC₁₋₂₂-alkyl group, C₁₋₂₂-alkylaryl group, an aryl group, a C₂₋₂₀-alkylsulfide C₁₋₂₂ alkyl group, C₂₋₂₀-alkylene sulfide alkyl group, aC₂₋₂₀-alkyl sulfide aryl group, a C₂₋₂₀-alkylene sulfide aryl group; thefree valences of the silicate oxygen atoms are saturated by one or moreof:

a silicon atom of other groups of Formula I, hydrogen, a linear orbranched C₁₋₂₂-alkyl group, an end group R₃M¹O_(1/2), a cross-linkingbridge member or by a chain R_(q)M¹OR¹)_(g)O_(k/2) orAl(OR¹)_(3-h)O_(h/2) or RAl(OR¹)_(2-r)O_(r/2);

wherein

M¹ is Si or Ti; R and R¹ are independently selected from a linear orbranched C₁₋₂₂ alkyl group, an aryl group and a C₁₋₂₂-alkylaryl group;

k is an integer from 1 to 3, q is an integer from 1 to 2 and g is aninteger from 0 to 2 such that g+k+q=4;

h is an integer from 1 to 3; and

r is an integer from 1 to 2;

or an oxo metal bridging systems where the metal is zirconium, boron,magnesium, iron, nickel or a lanthanide;

a, b and c are integers such that the ratio of a:b is from 0.00001 to100000 and a and b are always present and when c is greater than 0 theratio of c to a+b is from 0.00001 to 100000.

Where an end group and/or cross linker and/or polymer chain is used, itis preferred that the ratio of end group, cross linker or polymer chainsto a+b+c is from 0 to 999:1 preferably 0.001 to 999:1 and especially0.01 to 99:1.

Compounds of Formula I according to the invention are suitable for useas catalysts, especially as as heterogeneous acid catalysts. Compoundsof Formula I are suitable for treating a feedstock of a reduction,elimination, alkylation, polymerisation, arylation, acylation,isomerisation, esterification, trans-esterification, elimination orrearrangement reaction. Suitably the feedstock is treated and thereaction carried out using a compound obtainable by a process accordingto the invention by contacting the compound with one or more reactantsin the feedstock to catalyse the reaction.

In a preferred embodiment, the process comprises treating a feedstockcomprising i) a carboxylic acid or compound comprising a reactablecarboxylate moiety; and ii) and a compound comprising an alcohol groupwith a compound obtainable by a process according to the invention bycontacting the compound and the feedstock to esterify the carboxylicacid or compound comprising a reactable carboxylate moiety. Preferablythe carboxylic acid comprises a C₁₋₂₂ carboxylic acid, preferably aC₆₋₂₂ carboxylic acid. Examples of suitable carboxylic acids andreactable carboxylate moieties include maleic acid, acetic anhydride,dodecanoic acid, octanoic acid, oleic acid

Suitably, the alcohol containing-compound comprises a polyalkyleneglycol, preferably having from 1 to 100 alkylene oxide units, forexample polyethylene glycol having an average molecular weight of 400.The alcohol may comprise a polyol, preferably glycerol, a glycol forexample neopentyl glycol, trimethylolpropane, and pentaerythritol. Thealcohol may be a C₁ to C₂₂, preferably C₆ to C₁₂ monoalcohol and may belinear, for example octan-1-ol, or branched, for example 2-ethylhexanol.

Compounds of Formula I in which X is hydrogen have been found to beuseful for catalysing a wide range of reactions, particularly reactionswhich are conventionally acid catalysed such as condensation reactionsof aldehydes and ketones, ketalisation and acetalisation reactions,dehydration of olefins, a wide range of rearrangement and fragmentationreactions, isomerisations, esterifications and the trans-esterificationof carboxylate esters. A particular advantage is that a materialcombining the advantages of a stable silica framework and the strongacid strength of the sulfonic acid group enables reactions to beconducted at high temperatures and pressures.

The invention will now be described in detail with reference toillustrative examples of the invention.

EXAMPLE 1

A mixture of vinyltrimethoxysilane (42.9 mL, 240 mmol) and di-tert-butylperoxide (2 mL) was added dropwise over 20 min to a stirred solution ofthioacetic acid (26.6 mL, 312 mmol) at reflux (86° C.). Reflux wasmaintained for a total of 3 h and the solution cooled and then addeddropwise to a stirred solution of concentrated nitric acid (68%, 210 mL)at room temperature. After addition was complete, the mixture was heatedat reflux for a further 90 min and then diluted to a volume of 510 mLwith deionised water. Silica (171 g) was added and the mixture stirredat reflux for 6 h and then cooled. The filtered solid was washed withwater (3×500 mL) and then methanol (3×500 mL) and dried to give acompound of Formula I where c=0.

EXAMPLE 2

A mixture of vinyltrimethoxysilane (42.9 mL, 240 mmol) and di-tert-butylperoxide (2 mL) was added dropwise over 20 min to a stirred solution ofthioacetic acid (26.6 mL, 312 mmol) at reflux (86° C.). Reflux wasmaintained for a total of 3 h. A Dean-Stark head was then added andexcess thioacetic acid (7 mL) removed by distillation. The solution wascooled and then added dropwise to a stirred solution of concentratednitric acid (68%, 210 mL) at room temperature. After addition wascomplete, the mixture was heated at reflux for a further 90 min and thendiluted to a volume of 490 mL with deionised water. Silica (180 g) wasadded and the mixture stirred at reflux for 6 h and then cooled. Thefiltered solid was washed with water (3×500 mL) and then methanol (3×500mL) and dried to give a compound of Formula I where c=0.

EXAMPLE 3

A mixture of vinyltrimethoxysilane (166.5 mL, 1.09 mol) anddi-tert-butyl peroxide (5 mL) was added dropwise over 20 min to astirred solution of thioacetic acid (100 mL, 1.42 mol) at reflux (86°C.). Reflux was maintained for a total of 3 h and the solution cooledand then added dropwise to a stirred solution of concentrated nitricacid (68%, 470 mL) at room temperature. After addition was complete, themixture was heated at reflux for a further 90 min and then diluted to avolume of 2.34 L with deionised water. Butyltrimethoxysilane (9.72 g,54.5 mmol) and silica (779 g) were added and the mixture stirred atreflux for 6 h and then cooled. The filtered solid was washed with water(3×2.3 L) and then methanol (2×2.3 L) and dried to give a compound ofFormula I where V is butyl.

EXAMPLE 4

A mixture of vinyltrimethoxysilane (83.3 mL, 545 mmol) and di-tert-butylperoxide (2 mL) was added dropwise over 20 min to a stirred solution ofthioacetic acid (50.0 mL, 710 mmol) at reflux (86° C.). Reflux wasmaintained for a total of 6 h and the solution cooled and then addeddropwise to a stirred solution of concentrated nitric acid (68%, 230 mL)at room temperature. After addition was complete, the mixture was heatedat reflux for a further 90 min and then diluted to a volume of 500 mLwith deionised water. A solution of tetraethyl orthosilicate (363 mL,1.64 mol) in methanol (500 mL) was added and the mixture was heated at50-60° C. for 14 days. The solid was milled, washed with water and thenmethanol and dried to give a compound of Formula I where c=0.

EXAMPLE 5

A mixture of vinyltrimethoxysilane (17.1 mL, 95 mmol) and thioaceticacid (10.6 mL, 125 mmol) were stirred at room temperature (18-28° C.)with UV irradiation for a total of 7 h. The solution was then addeddropwise to a stirred solution of concentrated nitric acid (68%, 85 mL)at room temperature. After addition was complete, the mixture was heatedat reflux for a further 90 min and then diluted to a volume of 200 mLwith deionised water. Silica (65 g) was added and the mixture stirred atreflux for 6 h and then cooled. The filtered solid was washed with water(3×200 mL) and then methanol (3×200 mL) and dried to give a compound ofFormula I where c=0.

EXAMPLE 6

Into a 75 L reactor was added thioacetic acid (6.93 kg, 91 mol) andtoluene (10.70 L).

Agitation was applied and the solution was heated to 90° C. Vinyltrimethoxy silane (10.37 kg, 70 mol) and di tert-butyl peroxide (150 mL)was added slowly over 30 min. The solution was stirred under reflux fora further 4 hours at this temperature whilst adding di-tert-butylperoxide every hour (400 mL in total) and then cooled. This solution wasadded into a stirred mixture of silica (50 kg) and toluene (120 L) in a500 L reactor. The mixture was heated at reflux for 4 hours and themethanol produced in the reaction was removed. The mixture was cooledand filtered. The solid was washed with methanol and dried. The solidwas then added to a stirred solution of nitric acid (69%, 150 L) at 114°C. for 4 hours to give a material of Formula I (56.5 kg) where c=0.

EXAMPLE 7

Vinyltrimethoxysilane (1.037 kg, 7 mol) and di-tert-butyl peroxide (150mL) was added to a stirred solution of mercaptoacetic acid (0.693 kg,9.1 mol) and toluene (1.7 L) at 90° C. The solution was stirred underreflux for 4 hours and then cooled to room temperature. This solutionalong with dodecyl trimethoxy silane (0.1 mol) was added into a stirredmixture of silica (5 kg) and toluene (12 L). The mixture was refluxedfor 4 hours and during this phase the methanol produced in the reactionwas removed. The mixture was cooled and filtered. The solid was washedwith methanol and dried. The solid was then added to a stirred solutionof nitric acid (69%) at 114 ° C. for 4 hours to give a material ofFormula I (56.5 kg) where V was dodecyl.

EXAMPLE 8

A mixture of vinyltrimethoxysilane (166.5 mL, 1.09 mol) anddi-tert-butyl peroxide (5 mL) was added dropwise over 20 min to astirred solution of thioacetic acid (100 mL, 1.42 mol) at reflux (86°C.). Reflux was maintained for a total of 3 h and the solution cooledand then added dropwise to a stirred solution of concentrated nitricacid (68%, 470 mL) at room temperature. After addition was complete, themixture was heated at reflux for a further 90 min and then diluted to avolume of 2.34 L with deionised water. 2-octylsulfidoethyltrimethoxysilane (54.5 mmol) and silica (779 g) were added and themixture stirred at reflux for 6 h and then cooled. The filtered solidwas washed with water (3×2.3 L) and then methanol (2×2.3 L) and dried togive a compound of Formula I where and V is 2-octylsulfideethyl.

EXAMPLE 9

A mixture of vinyltrimethoxysilane (166.5 mL, 1.09 mol) anddi-tert-butyl peroxide (5 mL) was added dropwise over 20 min to astirred solution of thioacetic acid (100 mL, 1.42 mol) at reflux (86°C.). Reflux was maintained for a total of 3 h and the solution cooledand then added dropwise to a stirred solution of concentrated nitricacid (68%, 470 mL) at room temperature. After addition was complete, themixture was heated at reflux for a further 90 min and then diluted to avolume of 2.34 L with deionised water. 2-octadecylsulfidoethyltrimethoxysilane (54.5 mmol) and silica (779 g) were added and themixture stirred at reflux for 6 h and then cooled. The filtered solidwas washed with water (3×2.3 L) and then methanol (2×2.3 L) and dried togive a compound of Formula I where and V is 2-octadecylsulfidoethyl.

EXAMPLE 10

A mixture of vinyltrimethoxysilane (166.5 mL, 1.09 mol) anddi-tert-butyl peroxide (5 mL) was added dropwise over 20 min to astirred solution of thioacetic acid (100 mL, 1.42 mol) at reflux (86°C.). Reflux was maintained for a total of 3 h and the solution cooledand added to sulfuric acid in water (10%, 450 mL). Hydrogen peroxide(30%, 376 mL, 4.36 mol) was added dropwise. After addition was complete,the mixture was heated at reflux for 30 min and then diluted to a volumeof 2.34 L with deionised water. Silica (779 g) was added and the mixturestirred at reflux for 6 h and then cooled. The filtered solid was washedwith water (3×2.3 L) and then methanol (2×2.3 L) and dried to give acompound of Formula I where c=0.

EXAMPLE 11

A mixture of maleic acid (23.2 g, 0.2 mol), 2-ethylhexanol (78.10 g, 0.6mol), and the compound from Example 1 (0.38 g, 0.4 wt %) was heated onan oil bath at 130° C. with stirring under reduced pressure (˜200 mbar).After 18 h, the mixture was cooled, filtered to recover catalyst, andanalysed to show 97% diester present.

EXAMPLE 12

A mixture of maleic acid (23.2 g, 0.2 mol), 2-ethylhexanol (78.10 g, 0.6mol), and the compound from Example 3 (0.38 g, 0.4 wt %) was heated onan oil bath at 120° C. with stirring under reduced pressure (˜200 mbar).After 18 h, the mixture was cooled, filtered to recover catalyst, andanalysed to 97% diester present.

EXAMPLE 13

A mixture of oleic acid (42.0 g, 148 mmol), glycerol (8.0 g, 87 mmol)and compound from Example 8 (0.5 g, 1 wt %) was heated with stirring to150° C. under a gentle nitrogen flow (˜0.1 L/min). After 24 h, themixture was cooled and the catalyst filtered off. The pale yellow oilwas analysed by standard titration techniques and found to have ahydroxy value of <0.1.

EXAMPLE 14

A mixture of oleic acid (42.0 g, 148 mmol), glycerol (8.0 g, 87 mmol)and compound from Example 1 (0.5 g, 1 wt %) was heated with stirring to150° C. under a gentle nitrogen flow (˜0.1 L/min). After 24 h, themixture was cooled and the catalyst filtered off. The pale yellow oilwas analysed by standard titration techniques and found to have ahydroxy value of <0.1.

EXAMPLE 15

A mixture of dodecanoic acid (19.4 g, 96.9 mmol), poly(ethylene glycol)(average molecular weight 400, 22.4 g, 56.0 mmol), and compound fromExample 1 (0.4 g, 1 wt %) was heated on an oil bath at 120° C. withstirring under a gentle nitrogen flow. After 21 h, the mixture wascooled, filtered to recover catalyst, and analysed to show completeconversion of the dodecanoic acid.

EXAMPLE 16

A mixture of dodecanoic acid (19.4 g, 96.9 mmol), poly(ethylene glycol)(average molecular weight 400, 22.4 g, 56.0 mmol), and compound fromExample 6 (0.4 g, 1 wt %) was heated on an oil bath at 120° C. withstirring under a gentle nitrogen flow. After 21 h, the mixture wascooled, filtered to recover catalyst, and analysed to show completeconversion of the dodecanoic acid.

EXAMPLE 17

A mixture of octanoic acid (46.2 g, 320 mmol, 3.2 eq),trimethylolpropane (13.8 g, 103 mmol, 1 eq), and the compound fromExample 1 (0.06 g, 0.1 wt %) was heated on an oil bath at 140° C. withstirring. After 24 h, the mixture was cooled, filtered to recovercatalyst, and analysed to show full conversion of the alcohol to diester(17%) and triester (83%).

EXAMPLE 18

A mixture of 1-octanol (40 mL, 252 mmol), acetic anhydride (26 mL, 278mmol) and compound from Example 1 (0.6 g, 1 wt %) was stirred at 16° C.for 2 h. The solution was filtered and excess acetic anhydride removedby distillation to give 1-octyl acetate as the only product.

EXAMPLE 19

Into a 75 L reactor was added thioacetic acid (6.93 kg, 91 mol) andtoluene (10.70 L). Agitation was applied and the solution was heated to90° C. Vinyl trimethoxy silane (10.37 kg, 70 mol) and di tert-butylperoxide (150 mL) was added slowly over 30 min. The solution was stirredunder reflux for a further 4 hours at this temperature whilst addingdi-tert-butyl peroxide every hour (400 mL in total) and then cooled.This solution was added into a stirred mixture of silica (50 kg) andnitric acid (120 L) in a 500 L reactor. The mixture was heated at refluxfor between 2 to 6 hours and the methanol produced in the reaction wasremoved. The mixture was cooled and filtered. The solid was washed withwater and methanol and dried to give a material of Formula I (56.5 kg)where c=0.

The stability of the catalyst was tested by refluxing in methanol for200 hours. The catalyst had a similar final acid loading after this testas to the loading before the test, indicating excellent stability.

EXAMPLE 20

The procedure of Example 19 was repeated but with the mixture beingrefluxed for between 12 and 24 hours. The stability of the catalyst wastested and shown to have retained the acid loading and showed excellentstability. Beyond 200 hours, the catalyst maintained its acid loadingfor a longer period than the catalyst of Example 19 indicating a higherlevel of stability.

The invention claimed is:
 1. A process for the production of a compoundof Formula I:[(O_(3/2))Si CH₂CH₂SO₃X]_(a) [Si(O_(4/2))]_(b) [VSi(O_(3/2))]_(c)   (I)wherein: X is selected from H, or M where M is a base or transitionmetal ion; V is a monovalent group which is optionally substituted andselected from a C₁₋₂₂-alkyl group, C₂₋₂₂-alkenyl group, a C₂₋₂₂-alkynylgroup, C₁₋₂₂-alkylaryl group, an aryl group, a C₂₋₂₀-alkyl sulfide C₁₋₂₂alkyl group, C₂₋₂₀-alkylene sulfide alkyl group, a C₂₋₂₀-alkyl sulfidearyl group, a C₂₋₂₀-alkylene sulfide aryl group; the free valences ofthe silicate oxygen atoms are saturated by one or more of: a siliconatom of other groups of Formula I, hydrogen, a linear or branchedC₁₋₂₂-alkyl group, an end group R₃SiO_(1/2),a cross-linking bridgemember or by a chain R_(q)Si(OR¹)_(g)O_(k/2)or Al(OR¹)_(3-h)O_(h/2) orRAl(OR¹)_(2-r)O_(r/2), wherein R and R¹ are independently selected froma linear or branched C₁₋₁₂ alkyl group, an aryl group and aC₁₋₂₂-alkylaryl group, k is an integer from 1 to 3, q is an integer from1 to 2 and g is an integer from 0 to 2 such that g +k +q =4, h is aninteger from 1 to 3; and r is an integer from 1 to 2; and, when present,the ratio of the mole sum of the end group, cross linker and/or polymerchain to a+b+c is from 0 to 999:1 a, b and c are integers such that theratio of a:b is from 0.00001 to 100000, a and b are always greater than0 and when c is greater than 0 the ratio of c to a+b is from 0.00001 to100000; the process comprising contacting in any order orsimultaneously: a) a compound of Formula II or precursor components ofthe compound of Formula II,(R³O)₃SiCH₂CH₂SC(=O)R²   (II) b) where R³ is hydrogen or a C_(l-6) alkylgroup and R² is a C₁₋₂₂ alkyl group, an inorganic support selected fromsilica, silica aluminate and alumina or with a compound selected fromSi(OR¹)₄ and mixture of Si(OR¹)₄ and Al(OR¹)₃; and optionally one ormore of (R³O)₃SiV, RSi(OR³)₃, (R)₂Si(OR³)₂ and (R)₃Si(OR³), Al(OR³)₃ andRAl(OR³)₂; and c) nitric acid or hydrogen peroxide; to produce thecompound of Formula I.
 2. A process according to claim 1 wherein theprocess comprises contacting a compound of Formula II: either with: a)an inorganic support selected from silica, silica aluminate and aluminaor with a compound selected from Si(OR¹)₄ and mixture of Si(OR¹)₄ andAl(OR¹)₃; and optionally one or more of (R³O)₃SiV, RSi(OR³)₃,(R)₂Si(OR³)₂ and (R)₃Si(OR³), Al(OR³)₃ and RAl(OR³)₂ to produce areaction product and contacting the reaction product with nitric acid orhydrogen peroxide to produce the compound of Formula I; or b) withnitric acid to produce a reaction product and contacting the reactionproduct and optionally one or more of (R³O)₃SiV, RSi(OR³)₃, (R)₂Si(OR³)₂and (R)₃Si(OR³), Al(OR³)₃ and RAl(OR³)₂ with an inorganic supportselected from silica, silica aluminate and alumina or with a compoundselected from Si(OR¹)₄ and mixture of Si(OR¹)₄ and Al(OR¹)₃; to producea compound of Formula I.
 3. A process according to claim 1 wherein thecompound of Formula II is present as a solution of the compound ofFormula II.
 4. A process according to claim 1 wherein compound ofFormula II is reacted with an inorganic support selected from silica,silica aluminate and alumina wherein the reaction is carried out at 20to 150° C. for between 10 minutes to 48 hours to produce the reactionproduct.
 5. A process according to claim 1 wherein the said processcomprises reacting a solution of Formula II, where R³ is hydrogen or aC₁₋₆ alkyl and R² is a C₁₋₆ alkyl, and optionally one or more of(R¹O)₃SiV, RSi(OR¹)₃, (R)₂Si(OR¹)₂ and (R)₃Si(OR¹), Al(OR¹)₃ andRAl(OR¹)₂ with the inorganic support at 80 to 150° C. for between 10minutes to 8 hours, and treating the resultant product with nitric acidat 20° C. to 130° C. for between 10 minutes to 8 hours.
 6. A processaccording to claim 1 wherein the contacting step comprises sol gellingthe compound of Formula II with a compound selected from Si(OR¹)₄ and amixture of Si(OR¹)₄ and Al(OR¹)₃ and optionally one or more of(R¹O)₃SiV, RSi(OR¹)₃, (R)₂Si(OR¹)₂ and (R)₃Si(OR¹), Al(OR¹)₃ andRAl(OR¹)₂ to produce a reaction product and contacting the reactionproduct with nitric acid or hydrogen peroxide to produce the compound ofFormula I.
 7. A process according to claim 1 wherein the reactionproduct is reacted with nitric acid at 0° C. to 150° C. for between 10minutes to 12 hours to produce a compound of Formula I.
 8. A processaccording to claim 1 comprising contacting a compound of Formula II withnitric acid to produce a reaction product and contacting the reactionproduct and optionally one or more of (R¹O)₃SiV, RSi(OR¹)₃, (R)₂Si(OR¹)₂and (R)₃Si(OR¹), Al(OR¹)₃ and RAl(OR¹)₂ with an inorganic supportselected from silica, silica aluminate and alumina or with a compoundselected from Si(OR¹)₄ and mixture of Si(OR¹)₄ and Al(OR¹)₃ to produce acompound of Formula I.
 9. A process according to claim 8 wherein thecompound of Formula II is contacted with nitric acid at a temperaturefrom 20-130° C. for 10 minutes to 48 hours.
 10. A process according toclaim 8 wherein the reaction product is reacted with the inorganicsupport selected from silica, silica aluminate and alumina at 20 to 140°C. for between 10 minutes to 48 hours.
 11. A process according to claim10 wherein the reaction is carried out for between 10 minutes and 8hours.
 12. A process according to claim 8 wherein a compound of FormulaII, wherein R¹ is hydrogen or a C₁₋₆ alkyl is treated with 50-70% nitricacid nitric acid at temperatures from 60-130° C. for 10 minutes to 12hours.
 13. A process according to claim 1 where the integer c in FormulaI is zero, the free valences of the silicate oxygen atoms are saturatedby one or more of a silicon atom of other groups of Formula I, hydrogen,a linear or branched C₁₋₆-alkyl group; R³ in Formula II is hydrogen or aC₁₋₆ alkyl and R² is a C₁₋₆ alkyl.